WO2016110155A1

WO2016110155A1 - Organosilicon coating specially for matt weather resistance emas and preparation method thereof

Info

Publication number: WO2016110155A1
Application number: PCT/CN2015/094334
Authority: WO
Inventors: 陶云峰; 史亚杰; 张先银; 刘平; 姚红宇; 方辉; 刘洪�
Original assignee: 成都拓利科技股份有限公司; 中国民航科学技术研究院
Priority date: 2015-01-08
Filing date: 2015-11-11
Publication date: 2016-07-14
Also published as: CN105820753A; EP3243883A4; CN105820753B; JP2018508602A; US20180002568A1; JP6533829B2; US10370563B2; EP3243883A1

Abstract

An organosilicon coating specially for matt weather resistance EMAS, comprising: 80 to 130 parts by weight of α,ω-dihydroxy polydimethylsiloxane; 0.5 to 10 parts by weight of a linear polydimethylsiloxane with the end group being a hydroxy group; 1 to 10 parts by weight of fumed silica; 10 to 50 parts by weight of precipitated silica; 1 to 5 parts by weight of a colour masterbatch; 0.9 to 5 parts by weight of a catalyst organotin chelate; a cross-linking agent, comprising 1.5 to 7 parts by weight of methyltrimethylethylketoximinosilane, 1.5 to 7 parts by weight of vinyltrimethylethylketoximinosilane, and 1 to 7 parts by weight of aminopropyltriethoxysilane; 1.5 to 6 parts by weight of a delustering agent; and 250 to 350 parts by weight of a solvent. The coating has the properties of a low viscosity, high flow, relatively fast curing, a moderate strength, a good adhesion, a good matte effect, being environmentally friendly and the like.

Description

Matte weather resistant EMAS special silicone coating and preparation method thereof

Technical field

The invention relates to a matt weather resistant EMAS special silicone coating and a preparation method thereof.

technical background

Although air travel is the safest way to travel in the world, due to operational errors, mechanical failures, bad weather, etc., the aircraft may be able to rush out of the runway during the take-off and landing process, causing serious accidents and accidents. This is for aviation safety. One of the main threats. In recent years, as the number of flights has increased, the number of aircraft rushing out of the runway has also increased. In the case of a steady decline in the overall accident rate of the civil aviation industry, how to avoid the serious accidents of aircraft crashes after the aircraft rushed out of the runway has become an important issue facing the civil aviation industry. Especially for some airports, because there are natural obstacles outside the runway (such as rivers, lakes and seas, deep trenches, etc.), building facilities, or other environmental factors, it is difficult to build a runway end safety zone that meets the length requirements, or construction costs. Too high, or although there is a safe area that meets the ICAO minimum standards (classes 3 and 4 are 240 meters long), once the safety zone is rushed out, the consequences are particularly serious. In response to these problems, the United States took the lead in organizing the development of the Engineered Material Arresting System (EMAS) as an engineering alternative to the above-mentioned special airport that cannot extend the long-end safety zone.

The Characteristic Material Barrier System (EMAS) is a crushing material with specific mechanical properties. It is laid on the floor of the runway extension line in a thickness of tens of centimeters to form a resisting bed. Once the aircraft rushes out of the runway into the obstruction bed, the crushed material is broken under the rolling of the wheel to absorb the kinetic energy of the aircraft, and under the premise of ensuring the safety of the aircraft and the aircraft, the aircraft gradually decelerates and finally stops in the intercepting bed. . EMAS provides the last reliable safety barrier for aircraft that rush out of the runway.

Therefore, the host material of the EMAS system must have the following properties:

The main material has excellent water resistance;

The overall sealing of the arresting bed has excellent water resistance;

The top cover (or cover) has excellent UV and anti-aging capabilities;

Excellent weather resistance, weather-free: can be used in high winds, rain, snow days;

Safety in use: The whole system meets the requirements of flame retardant, fireproof, non-toxic and environmental protection;

Emergency rescue: does not hinder the evacuation of the occupant after the event and the emergency rescue vehicle approaches the aircraft;

Design life: 20 years;

Maintenance requirements: regular and simple maintenance;

Navigation and lighting facilities: no impact;

Construction period: 60-80 days.

The cover of the EMAS system is made of polyester, which has poor weather resistance and reflective problems. The poor weather resistance will result in short service life; the reflection will interfere with the pilot's line of sight and cause flight accidents. Therefore, it is necessary to improve the matt property of the polyester cover sheet. A matt special coating with a good weather resistance on the surface of the polyester cover is an efficient, economical and convenient measure.

The one-component room temperature curing silicone coating has excellent weather resistance, excellent high and low temperature resistance and good water resistance. It can be used for a long time in the range of -60 to 200 °C; the theoretical service life can reach 20 years; it does not absorb heat during heating, does not exotherm, has small shrinkage after curing, and has good adhesion to polyester materials. And the construction is convenient and easy to repair, which greatly reduces the long-term maintenance cost. At the same time, its body is non-toxic and environmentally friendly. After adding a certain matt material, it has excellent matt properties and has the functions of adhesion, sealing, insulation and waterproof protection. Therefore, applying it to an EMAS facility will have enormous social and economic benefits.

Summary of the invention

The invention provides a gray low viscosity, high flow, fast curing, moderate strength, good adhesion, matt effect for the use characteristics and quality requirements of the EMAS system special silicone coating required for the polyester cover. Good, environmentally friendly, matt weather resistant EMAS special silicone coating.

The matt weather resistant EMAS special silicone coating of the present invention comprises:

α,ω-dihydroxypolydimethylsiloxane: 80 to 130 parts by weight, preferably 90 to 120 parts by weight, more preferably 95 to 115 parts by weight;

a linear polydimethylsiloxane having a hydroxyl group end group: 0.5 to 10 parts by weight, preferably 0.8 to 7 parts by weight, more preferably 1 to 3 parts by weight;

Gas phase process white carbon black: 1 to 10 parts by weight, preferably 2 to 7 parts by weight, more preferably 3 to 5 parts by weight;

Precipitated white carbon black: 10 to 50 parts by weight, preferably 13 to 40 parts by weight, more preferably 15 to 30 parts by weight;

Color master batch: 1 to 5 parts by weight, preferably 1.5 to 2.5 parts by weight;

a catalyst organotin chelate (for example, dibutyltin dilaurate, dioctyltin dilaurate, stannous octoate, etc.): 0.9 to 5 parts by weight, preferably 1 to 3 parts by weight;

Crosslinking agent: comprising 1.5 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 parts by weight, of methyl tributol sulfonyl silane, 1.5 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 parts by weight of vinyl tributol sulfonyl silane, and 1 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 aminopropyltriethoxysilane;

a matting agent (for example, L-1030 (produced by TTK Co., Ltd., Korea), polyether modified amine wax silane): 1.5 to 6 parts by weight, preferably 2 to 4 parts by weight;

Solvent: 250 to 350 parts by weight, preferably 280 to 320 parts by weight. The solvent is, for example, a hydrocarbon or petroleum ether solvent such as 120# gasoline, 200# gasoline or 90-120# petroleum ether.

In the present invention, the crosslinking agent is a combination of methyl tributyl sulfonyl silane, vinyl tributol sulfonyl silane, and aminopropyl triethoxy silane, and the crosslinking agent methyl tributol sulfonyl silane The reaction activity is low, and the reaction activity of vinyltributyl ketone silane is high, and the combination of the two can effectively control the reaction speed. Aminopropyltriethoxysilane takes into account the effects of crosslinking and thickening.

In the present invention, the fumed silica and the precipitated silica are used in combination, and the fumed silica (SiO ₂ ) has a more excellent reinforcing ability, but the product has relatively poor fluidity; the precipitated silica is black. The ability to reinforce is poor, but product liquidity is relatively good. Mixed use can achieve good reinforcement while ensuring good fluidity.

The α,ω-dihydroxypolydimethylsiloxane in the present invention is preferably a low-viscosity α,ω-dihydroxypolydimethylsiloxane as a base rubber, and has a molecular weight of 26,000 to 150,000, preferably 58,000 to 7,800. The range is from 1000 to 150,000, preferably from 8,000 to 18,000; including the trade name of 107 glue, manufacturers Shin-Etsu, Toshiba, Jiangxi Spark, Zhejiang Xin'an Chemical, etc.

The linear polydimethylsiloxane having a hydroxyl group having a terminal group used in the present invention has a molecular weight ranging from 2,000 to 139000, preferably from 20,000 to 30,000, and a viscosity ranging from 20 to 10,000, preferably from 500 to 1,000, including a trade name of dimethicone. Dow Corning, Wacker, Zhejiang Xin'anhua, Jiangxi Xinghuo, etc., use it as an additive to increase the hydroxyl content, use white carbon black to reinforce, aminopropyltriethoxysilane as a binder, plus special matting auxiliary and auxiliary 120# gasoline, 200# gasoline or 90～120# petroleum ether is used as solvent to control the production process, and it can be used for EMAS specialization with good weather resistance, good mattility, fast curing, moderate strength, good adhesion and environmental protection. Silicone coatings.

Appearance: dark gray liquid, consistent with EMAS color;

Viscosity: 720mPa.s, which is good for spraying;

Dry time: 15min (25 ° C, 50%), which is conducive to rapid curing;

Shear strength: >1.3MPa, bonding with cement module, effective waterproofing;

Moderate strength: The tensile strength of the cured coating is greater than 1.5 MPa, such as between 1.5 MPa and 2.0 MPa, more preferably between 1.55 MPa and 1.9 MPa, and particularly preferably between 1.6 MPa and 1.8 MPa. The elongation is greater than 150%, for example between 150% and 220%, preferably between 155% and 200%, more preferably between 160% and 190%. Too low strength and too low elongation may cause cracks and peeling of the cover coating. Excessive strength and excessive elongation may cause the wheel to be crushed, resulting in failure of the EMAS system. .

Matting: Gloss ≤ 30%, to ensure that the pilot's line of sight is not disturbed;

Solid content: ≥ 25%. However, it is preferably ≤ 40% by weight, more preferably ≤ 35% by weight.

The viscosity of the coating (25 ° C) is 500 mPa.s - 900 mPa.s, preferably 600 mPa.s - 800 mPa.s, more preferably preferably 680 mPa.s - 740 mPa.s, for example 720 mPa.s.

Environmental protection: no corrosion to the substrate.

Another aspect of the invention relates to a method of preparing a matt weather resistant EMAS-specific silicone coating, the method comprising the steps of:

Mixing α,ω-dihydroxypolydimethylsiloxane, linear polydimethylsiloxane having a hydroxyl group end group, fumed silica, and precipitated silica, grinding, and then at 90-160 Drying under vacuum under vacuum conditions (for example, 2-5 hours, preferably 3-4 hours), then adding color masterbatch, catalyst, crosslinking agent, matting agent at a temperature of 40-60 ° C for stirring (for example, 20 minutes) ～2 hours, preferably 30 minutes to 1 hour, for example, 30 minutes), and further stirred with a solvent to obtain a product.

The patent adopts a trifunctional reactive reactive crosslinking agent as a silicone rubber. In the vulcanization process of the silicone rubber, the crosslinking agent reacts with the active end group of the silicone rubber polymer under the promotion of the catalyst, and the reaction is removed. The low molecular weight finally forms a crosslinked network of the silicone polymer to realize cross-linking and vulcanization of the silicone rubber.

In this reaction, there are two issues to be aware of:

1. The amount of cross-linking agent: In the preparation component of silicone rubber, part of the cross-linking agent participates in the pre-condensation reaction, in addition to a considerable amount of excess cross-linking agent, this part of the reactive small-molecule organosilane component is also One of the indispensable components of one-component room temperature vulcanized silicone rubber. Compared with the base rubber polymer of the polymer chain, the chemical reaction performance of the small molecule cross-linking agent is relatively more active. In the process of product packaging and the like, it may preferentially react with trace moisture in the process of contact with trace moisture. It acts as a water scavenger to avoid early cross-linking of the silicone rubber packaging process; it will act as a stabilizer during the storage of silicone rubber.

When the crosslinking agent is below a certain critical concentration, since the low concentration of the crosslinking agent is insufficient to form the silicone rubber polymer into a crosslinked network, the silicone rubber material is not crosslinked and vulcanized whether or not it is exposed to moisture. It is necessary to have a proper cross-linking agent concentration to ensure the normal cross-linking vulcanization rate of silicone rubber; however, if the cross-linking agent concentration is too large, a large excess of cross-linking agent will preferentially consume water when the silicone rubber material is exposed to moisture in the air. The portion, that is, the normal cross-linking reaction of the silicone rubber is delayed, so that the cross-linking vulcanization rate of the silicone rubber is significantly slowed down.

2, storage stability: general deketoxime type RTV-1 silicone rubber storage period of no more than 3 months, in order to solve this problem, this patent uses a kind of linear polydimethylsiloxane with hydroxyl group end group added to the base rubber The oxane is added with a hydroxyl group content, and the residual hydroxyl group in the base rubber and the water introduced by the filler are removed to improve the storage stability of the rubber compound.

The product of the invention has the advantages of low viscosity, high flow, fast curing, moderate strength, good adhesion, good matt effect and environmental protection.

Still another aspect of the invention relates to a cured coating obtained by curing the above coating or a cured coating obtained by the above method, wherein the cured coating has a tensile strength of between 1.5 MPa and 2.0 MPa, more preferably at 1.55 MPa. Between -1.9 MPa, particularly preferably between 1.6 MPa and 1.8 MPa; and/or, the cured coating has an elongation of more than 150%, for example between 150% and 220% Preferably, it is between 155% and 200%, more preferably between 160% and 190%.

detailed description

The invention is illustrated by the following examples, in the following examples, parts are by weight unless otherwise specified.

Example 1

Select α,ω-dihydroxypolydimethylsiloxane (107 gel, number average molecular weight 60,000, Shin-Etsu, Japan) 90 parts, linear polydimethylsiloxane with terminal hydroxyl group (dimethicone, number average Molecular weight 30000, Dow Corning) 1 part, 2 parts of fumed silica, 15 parts of precipitated silica, uniformly mixed in a kneader, transferred to a three-roll mill, uniformly transferred to a kneader The mixture was heated and stirred, and the temperature of the rubber was maintained at 100 ° C and the degree of vacuum was ≥ 0.085 Mpa, and the mixture was vacuum dried for 3 hours. Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of a special color masterbatch (domestic spray carbon black) is added, and the catalyst: 1 part of an organotin chelate (dibutyltin dilaurate), Crosslinking agent: 2.5 parts of methyl tributol sulfonyl silane, 2.5 parts of vinyl tributol sulfonyl silane, 2 parts of aminopropyl triethoxy silane, stirring at high speed for 20 minutes; adding matting agent (L-1030) 2.5 parts, stirring at high speed for 20 minutes, vacuuming for 10 minutes, adding 300 parts of 120# solvent gasoline, and stirring at high speed for 10 minutes to obtain a product.

Example 2

100 parts of α,ω-dihydroxypolydimethylsiloxane, 2 parts of linear polydimethylsiloxane with hydroxyl group end groups, 4 parts of fumed silica, 20 parts of precipitated silica, The kneading machine mixes evenly, the rubber material is transferred to a three-roller for grinding, and then transferred to a kneading machine to be heated and stirred. The temperature of the rubber compound is maintained at 120 ° C, the vacuum degree is ≥0.085 Mpa, and the vacuum is dried for 3 hours. . Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of black masterbatch is added, catalyst: 1.5 parts of organotin chelate, crosslinking agent: 3 parts of methyl tributyl ketone. Silane, 3 parts of vinyl tributol sulfonyl silane, 2.5 parts of aminopropyl triethoxy silane, stirring at high speed for 30 minutes; adding 3 parts of matting agent (L-1030), stirring at high speed for 20 minutes, stirring under vacuum 10 In minutes, 300 parts of 200# gasoline was added and stirred at high speed for 10 minutes to obtain a product.

Example 3

110 parts of α,ω-dihydroxypolydimethylsiloxane, 3 parts of linear polydimethylsiloxane with hydroxyl group end groups, 5 parts of fumed silica and 25 parts of precipitated silica, The kneading machine mixes evenly, the rubber compound is transferred to a three-roller for grinding, and then transferred to a kneading machine to be heated and stirred. The temperature of the rubber compound is maintained at 150 ° C, the vacuum degree is ≥0.085 Mpa, and the vacuum is dried for 3 hours. . Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of black masterbatch is added, catalyst: 2.5 parts of organotin chelate, crosslinking agent: 3.5 parts of methyl tributyl ketone. Silane, 3 parts of vinyl tributol sulfonyl silane, 3 parts of aminopropyl triethoxy silane, stirring at high speed for 30 minutes; adding 3.5 parts of matting agent (L-1030), stirring at high speed for 20 minutes, stirring under vacuum 10 In minutes, 300 parts of 90-120# petroleum ether was added, and the mixture was stirred at high speed for 10 minutes to obtain a product.

Comparative example 1

100 parts of α,ω-dihydroxypolydimethylsiloxane, 2 parts of linear polydimethylsiloxane with hydroxyl group end groups, 4 parts of fumed silica, 20 parts of precipitated silica, The kneading machine mixes evenly, the rubber material is transferred to a three-roller for grinding, and then transferred to a kneading machine to be heated and stirred. The temperature of the rubber compound is maintained at 120 ° C, the vacuum degree is ≥0.085 Mpa, and the vacuum is dried for 3 hours. . Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of black masterbatch is added, catalyst: 1.5 parts of organotin chelate, crosslinking agent: 3 parts of methyl tributyl ketone. Silane, 3 parts of vinyltributyl ketone thiosilane, 2.5 parts of aminopropyltriethoxysilane, stirring at high speed for 30 minutes; adding 300 parts of 120# solvent gasoline, stirring at high speed for 10 minutes to obtain a product. This product has no matting effect because no matting agent is added.

Comparative example 2

100 parts of α,ω-dihydroxypolydimethylsiloxane, 2 parts of linear polydimethylsiloxane with hydroxyl group end groups, 4 parts of fumed silica, 20 parts of precipitated silica, The kneading machine mixes evenly, the rubber material is transferred to a three-roller for grinding, and then transferred to a kneading machine to be heated and stirred. The temperature of the rubber compound is maintained at 120 ° C, the vacuum degree is ≥0.085 Mpa, and the vacuum is dried for 3 hours. . Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of black masterbatch is added, catalyst: 1.5 parts of organotin chelate, crosslinking agent: 3 parts of methyl tributyl ketone. Silane, 3 parts of vinyl tributol sulfonyl silane, 2.5 parts of aminopropyl triethoxy silane, stirring at high speed for 30 minutes; adding 3 parts of tung oil, stirring at high speed for 20 minutes, adding 300 parts of 120# solvent gasoline, stirring at high speed 10 minutes to get the product. The use of tung oil as a matting agent has poor matting ability.

Comparative example 3

100 parts of α,ω-dihydroxypolydimethylsiloxane, 2 parts of linear polydimethylsiloxane with hydroxyl group end groups, 4 parts of fumed silica, 20 parts of precipitated silica, The kneading machine mixes evenly, the rubber material is transferred to a three-roller for grinding, and then transferred to a kneading machine to be heated and stirred. The temperature of the rubber compound is maintained at 120 ° C, the vacuum degree is ≥0.085 Mpa, and the vacuum is dried for 3 hours. . Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of black masterbatch is added, catalyst: 1.5 parts of organotin chelate, crosslinking agent: 3 parts of methyl tributyl ketone. Silane, 3 parts of vinyltributyl ketone thiosilane, 2.5 parts of aminopropyltriethoxysilane, stirring at high speed for 30 minutes; adding 3 parts of matting powder (TS100), stirring at high speed for 20 minutes, adding 120# solvent gasoline 300 The mixture was stirred at high speed for 10 minutes to obtain a product. In this embodiment, matting powder is used as a matting agent, and the matting ability is poor.

Comparative example 4

Select α,ω-dihydroxypolydimethylsiloxane (107 gel, molecular weight 60,000, Shin-Etsu, Japan) 100 parts, linear polydimethylsiloxane with terminal group of trimethylsiloxy (Qingdao Zhongbao Chemical) Ltd.) 1 part, 2 parts of fumed silica, 15 parts of precipitated white carbon black, uniformly mixed in the kneader, transferred to the three-roller for grinding, evenly transferred to the kneading machine for temperature stirring Keep the temperature of the rubber at 100 ° C and the vacuum degree ≥ 0.085 Mpa, and dry under vacuum for 3 hours. Then put into the planetary stirring tank, when the sealing temperature of the rubber is in the range of 50 °C, add special color masterbatch (domestic spray carbon black) 2.2 Parts, catalyst: 1 part organotin chelate (dibutyltin dilaurate), crosslinker: 2.5 parts methyl tributyl sulfonyl silane, 2.5 parts vinyl tributyl sulfonyl silane, 2 parts aminopropyl Triethoxysilane, stirring at high speed for 20 minutes; adding 2.5 parts of matting agent (L-1030), stirring at high speed for 20 minutes, stirring under vacuum for 10 minutes, adding 300 parts of 120# solvent gasoline, and stirring at high speed for 10 minutes to obtain a product.

Comparative example 5

Select α,ω-dihydroxypolydimethylsiloxane (107 gel, molecular weight 60,000, Shin-Etsu, Japan) 90 parts, linear polydimethylsiloxane with terminal hydroxyl group (dimethicone, molecular weight 30000, Dow Corning 1 part, 2 parts of fumed silica, 15 parts of precipitated white carbon black, uniformly mixed in the kneader, transferred to the three-roller for grinding, evenly transferred to the kneader for warming and stirring, keeping The temperature of the rubber was 100 ° C and the vacuum was ≥0.085 Mpa, and the mixture was vacuum dried for 3 hours. Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of a special color masterbatch (domestic spray carbon black) is added, and the catalyst: 1 part of an organotin chelate (dibutyltin dilaurate), Crosslinking agent: 2.5 parts of methyl tributol sulfonyl silane, 5 parts of vinyl tributol sulfonyl silane, stirring at high speed for 20 minutes; adding 2.5 parts of matting agent (L-1030), stirring at high speed for 20 minutes, vacuuming After stirring for 10 minutes, 300 parts of 120# solvent gasoline was added, and the mixture was stirred at high speed for 10 minutes to obtain a product.

Comparative example 6

Select α,ω-dihydroxypolydimethylsiloxane (107 gel, molecular weight 60,000, Shin-Etsu, Japan) 90 parts, linear polydimethylsiloxane with terminal hydroxyl group (dimethicone, molecular weight 30000, Dow Corning 15 parts, 2 parts of fumed silica, 15 parts of precipitated white carbon black, uniformly mixed in the kneader, transferred to the three-roller for grinding, evenly transferred to the kneader for warming and stirring, keeping The temperature of the rubber was 100 ° C and the vacuum was ≥0.085 Mpa, and the mixture was vacuum dried for 3 hours. Then, it is put into the planetary stirring tank. When the sealing temperature of the rubber is in the range of 50 ° C, 2.2 parts of a special color masterbatch (domestic spray carbon black) is added, and the catalyst: 1 part of an organotin chelate (dibutyltin dilaurate), Crosslinking agent: 2.5 parts of methyl tributol sulfonyl silane, 2.5 parts of vinyl tributol sulfonyl silane, 2 parts of aminopropyl triethoxy silane, stirring at high speed for 20 minutes; adding matting agent (L-1030) 2.5 parts, stirring at high speed for 20 minutes, vacuuming for 10 minutes, adding 300 parts of 120# solvent gasoline, and stirring at high speed for 10 minutes to obtain a product.

Performance testing:

The prepared rubber material is poured into a trough and naturally leveled to form a sheet having an average thickness of 2 mm. The sheet is vulcanized at room temperature for 7 days, and the vulcanized sheet is cut into a dumbbell-shaped strip by a sample preparation machine, and the reference is made with reference to GB/T 528 standard. The electronic universal testing machine tested its tensile strength and elongation at break, and the tensile rate was 50 mm/min. The measurement of the dry time was based on the GB/T 13477.5-2002 standard.

Matte: Spray the special silicone coating on the polyester cover. The thickness of the cured coating is between 0.2 and 0.25mm. After curing for seven days, flash the light with a flashlight and illuminate the cover at a 45-degree angle with the cover. The gloss is compared with the standard sample. If the extinction is worse than the standard sample, it is unqualified. If it is consistent with or better than the standard template, it is qualified.

According to the experiment, it is found that for the requirements of the EMAS system, the dry time can not be longer than 30 minutes, the gloss is less than 30%, the viscosity is between 700-840 mPa.s, the shear strength is not less than 1.2Mpa, and the tensile strength is Between 1.5-2Mpa, the elongation is between 150-200%, and the hardness is between 25-35. The solid content is not less than 25%.

Results and discussion:

1. Comparison of products and reference products:

Table 1 Comparison of performance between examples and comparative examples

It can be seen that: Comparative Example 1, 2 gloss is too large, does not meet the matt requirements; Comparative 2 strength is low, Comparative 3 strength is high and elongation is low, does not meet the customer's moderate requirements; Comparative 3 The surface drying time is too long and does not meet the construction requirements; the comparative examples 4 and 5 have high strength and insufficient elongation, and the comparative example 6 has low strength and low hardness. Only the indicators of the examples meet the requirements of EMAS.

2. The effect of different cross-linker fractions on the curing speed of the product:

Table 2 Relationship between the number of crosslinkers and the curing speed of the product

It can be seen that when the crosslinking agent is lower than a certain critical concentration, since the low concentration of the crosslinking agent is insufficient to form the crosslinked network of the silicone rubber polymer, the silicone rubber material will not crosslink and vulcanize whether or not it is exposed to moisture; When the concentration of the cross-linking agent is too large, when the silicone rubber material is exposed to moisture in the air, a large amount of excess cross-linking agent will preferentially consume water, that is, delaying the normal cross-linking reaction of the silicone rubber, and also making the silicone weather-resistant coating. The rate of co-vulcanization slows down. The base rubber includes α,ω-dihydroxypolydimethylsiloxane and a linear polydimethylsiloxane whose terminal group is a hydroxyl group.

3. Product heat aging experiment:

Table 3 Example 1 product heat aging performance

It can be seen that after the product of Example 1 is vulcanized and subjected to heat aging test at 200 ° C for 24 h, its hardness, tensile strength, elongation and shear strength of aluminum and other indexes do not change much, especially after 250 ° C × 72 h high temperature. Its performance can still be maintained after aging.

4, product storage stability:

Table 4 Example 1 product storage performance

It can be seen that after storage for half a year, its main performance does not change much. The reason is that linear polydimethylsiloxane with hydroxyl group end group is added, hydroxyl content is added, and residual hydroxyl groups and fillers in the base rubber are removed. The moisture is added to improve the storage stability of the rubber.

Claims

A matt weather resistant EMAS special silicone coating comprising:

α,ω-dihydroxypolydimethylsiloxane: 80 to 130 parts by weight, preferably 90 to 120 parts by weight, more preferably 95 to 115 parts by weight;

a linear polydimethylsiloxane having a hydroxyl group end group: 0.5 to 10 parts by weight, 0.8 to 7 parts by weight, more preferably 1 to 3 parts by weight;

Gas phase process white carbon black: 1 to 10 parts by weight, preferably 2 to 7 parts by weight, more preferably 3 to 5 parts by weight;

Precipitated white carbon black: 10 to 50 parts by weight, preferably 13 to 40 parts by weight, more preferably 15 to 30 parts by weight;

Color master batch: 1 to 5 parts by weight, preferably 1.5 to 2.5 parts by weight;

Catalyst organotin chelate: 0.9 to 5 parts by weight, preferably 1 to 3 parts by weight;

Crosslinking agent: comprising 1.5 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 parts by weight, of methyl tributol sulfonyl silane, 1.5 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 parts by weight of vinyl tributol sulfonyl silane, and 1 to 7 parts by weight, preferably 2 to 6 parts by weight, preferably 3 to 5 aminopropyltriethoxysilane;

a matting agent: 1.5 to 6 parts by weight, preferably 2 to 4 parts by weight;

Solvent: 250 to 350 parts by weight, preferably 280 to 320 parts by weight.
The silicone coating according to claim 1, wherein the α,ω-dihydroxypolydimethylsiloxane is a low viscosity α,ω-dihydroxypolydimethylsiloxane having a molecular weight ranging from 26,000 to 150,000, preferably 58,000. ～7800, the viscosity ranges from 1,000 to 150,000, preferably from 8,000 to 18,000.
The silicone coating according to claim 1 or 2, wherein the linear polydimethylsiloxane having a hydroxyl group at a terminal group has a number average molecular weight of from 2,000 to 139000, preferably from 20,000 to 30,000, and a viscosity in the range of from 20 to 10,000 cP, preferably 500. ~1000cP.
The silicone coating according to any one of claims 1 to 3, wherein the catalyst is selected from the group consisting of dibutyltin dilaurate, dioctyltin dilaurate or stannous octoate.
The silicone coating according to any one of claims 1 to 4, wherein the solvent is a hydrocarbon, a petroleum ether solvent such as 120# gasoline, 200# gasoline or 90-120# petroleum ether; and/or a color masterbatch The material is carbon black, preferably spray black.
The silicone coating according to any one of claims 1 to 5, wherein the matting agent is L-1030 or a polyether modified amine wax silane; and/or

The solids content of the coating is between 25% and 40% by weight; and/or

The viscosity of the coating (25 ° C) is 500 mPa.s - 900 mPa.s, preferably 600 mPa.s - 800 mPa.s, more preferably preferably 680 mPa.s - 740 mPa.s, for example 720 mPa.s.
A method of preparing a matt weather resistant EMAS-specific silicone coating according to any one of claims 1 to 6, the method comprising the steps of:

Mixing α,ω-dihydroxypolydimethylsiloxane, linear polydimethylsiloxane having a hydroxyl group end group, fumed silica, and precipitated silica, grinding, and then at 90-160 °C, vacuum drying under vacuum, then add color masterbatch, catalyst, cross-linking agent, matting agent at a temperature of 40-60 ° C, and then add solvent to stir to obtain the product.
A method of preparing a cured coating of a matt weather resistant EMAS-specific silicone coating according to any one of claims 1 to 6, the method comprising the steps of:

Mixing α,ω-dihydroxypolydimethylsiloxane, linear polydimethylsiloxane having a hydroxyl group end group, fumed silica, and precipitated silica, grinding, and then at 90-160 °C, under vacuum, vacuum drying, stirring, then adding color masterbatch, catalyst, cross-linking agent, matting agent at a temperature of 40-60 ° C, stirring, adding solvent, and then curing, to obtain a cured coating product.
a cured coating obtained by curing the coating according to any one of claims 1 to 7 or a cured coating obtained by the method of claim 8, wherein the cured coating has a tensile strength of 1.5 MPa to 2.0 MPa. More preferably, it is between 1.55 MPa and 1.9 MPa, particularly preferably between 1.6 MPa and 1.8 MPa; and/or the cured coating has an elongation of more than 150%, for example between 150% and 220%, It is preferably between 155% and 200%, more preferably between 160% and 190%.